Gas detection device with graphene membrane

ABSTRACT

Technologies are generally described for gas filtration and detection devices. Example devices may include a graphene membrane and a sensing device. The graphene membrane may be perforated with a plurality of discrete pores having a size-selective to enable one or more molecules to pass through the pores. A sensing device may be attached to a supporting permeable substrate and coupled with the graphene membrane. A fluid mixture including two or more molecules may be exposed to the graphene membrane. Molecules having a smaller diameter than the discrete pores may be directed through the graphene pores, and may be detected by the sensing device. Molecules having a larger size than the discrete pores may be prevented from crossing the graphene membrane. The sensing device may be configured to identify a presence of a selected molecule within the mixture without interference from contaminating factors.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is the U.S. National Stage filing under 35 U.S.C §371of International Application No. PCT/US12/67490 filed on Nov. 30, 2012.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

The emergence of a proliferous use of hydrogen in a variety ofindustries motivates sensing devices that can reliably detect thepresence of hydrogen, an explosive gas. Some factors that may beconsidered when choosing sensing devices may include power consumption,lifetime, and sensitivity to selected molecules. Sensing devices can bedeveloped to be highly sensitive to hydrogen; however, the sensitivityof the sensing devices may be diminished due to factors such astemperature, humidity, and interference by the presence of contaminatingmolecules.

SUMMARY

The following summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

The present disclosure generally describes compositions, methods,apparatus, systems, devices, and/or computer program products related tomanufacturing or using perforated graphene, for example, as part ofmembrane which may be used for selective gas detection employing agraphene membrane.

According to some examples embodiments, the present disclosure describesa gas detection device. The gas detection device may include asubstrate, a sensing device coupled to the substrate, the sensing deviceconfigured to detect a presence of one or more gases, and a graphenemembrane coupled to the sensing device, the graphene membrane includinga plurality of discrete pores having a size-selective to pass of the oneor more gases across the graphene membrane such that the sensing devicemay be operable to detect the presence of the one or more gases.

According to other example embodiments, the present disclosure alsodescribes various methods of detecting a gas molecule in a fluid mixtureincluding one or more gases. An example method may include exposing thefluid mixture, which includes at least a first gas molecule and a secondgas molecule to a graphene membrane such that the fluid mixture may bebrought in contact with the graphene membrane, where the graphenemembrane includes a plurality of discrete pores having a size-selectivefor the passage of the first gas molecule but not the second gasmolecule, selectively permeating the first gas molecule through thediscrete pores of the graphene membrane, detecting the first gasmolecule with a sensing device, and/or identifying the presence of thefirst gas molecule with sensing device.

According to further example embodiments, the present disclosure alsoincludes various methods of forming a gas detection device. An examplemethod may include providing a substrate to provide support a sensingdevice and a graphene membrane, coupling the sensing device with thesubstrate, where the sensing device may be operable to detect a presenceof one or more gases included in a fluid mixture, and/or coupling thegraphene membrane with the sensing device, where the graphene membraneincludes a plurality of discrete pores having a size-selective for thepassage of the one or more gases across the graphene membrane fordetection by the sensing device.

According to yet other example embodiments, the present disclosure alsodescribes a system for manufacturing a gas detection device. The systemmay include a controller configured by instructions stored thereon tofacilitate manufacturing of the gas detection device employing agraphene source, a substrate source, and a sensing device applicator.The controller may be operable to configure the graphene source toprovide a graphene membrane, where the graphene membrane includes aplurality of discrete pores having a size-selective for the passage ofone or more gases included in a fluid mixture across the graphenemembrane, configure the substrate source to provide a substrate tosupport the graphene membrane, and configure the sensing deviceapplicator to contact a sensing device with the substrate, where thesensing device is configured to detect a presence of the one or moregases contained in the fluid mixture that cross the graphene membrane.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of this disclosure will become morefully apparent from the following description and appended claims, takenin conjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings, in which:

FIG. 1 is a conceptual drawing of an example perforated graphenemonolayer;

FIG. 2 illustrates an example graphene monolayer showing passivatedpores of the graphene monolayer;

FIG. 3 is conceptual drawing of a side view of an example membraneillustrating a method of separating a gas mixture of two molecules;

FIG. 4 is a conceptual drawing of a side view of an example membranethat includes an example perforated graphene monolayer in contact with asensing device and a permeable substrate for detecting a gas molecule ina gas mixture;

FIG. 5 is a block diagram of an automated system that may be used formaking an example gas filtration and detection device;

FIG. 6 illustrates a general purpose computing device that may be usedto control the automated system of FIG. 5 or similar manufacturingequipment in making an example membrane;

FIG. 7 is a flow diagram showing steps that may be used for detecting agas molecule that crosses a graphene membrane; and

FIG. 8 illustrates a block diagram of an example computer programproduct that may be used to control the automated system of FIG. 5 orsimilar manufacturing equipment in making an example membrane,

all arranged in accordance with at least some embodiments as describedherein.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented herein. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe Figures, can be arranged, substituted, combined, separated, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated herein.

This disclosure is generally drawn, inter alia, to compositions,methods, apparatus, systems, devices, and/or computer program productsrelated to manufacturing or using perforated graphene, for example, aspart of membrane which may be used in gas separation.

Briefly stated, technologies are generally described for gas filtrationand detection devices. Example devices may include a graphene membraneand a sensing device. The graphene membrane may be perforated with aplurality of discrete pores having a size-selective to enable one ormore molecules to pass through the pores. A sensing device may beattached to a supporting permeable substrate and coupled with thegraphene membrane. A fluid mixture including two or more molecules maybe exposed to the graphene membrane. Molecules having a smaller diameterthan the discrete pores may be directed through the graphene pores, andmay be detected by the sensing device. Molecules having a larger sizethan the discrete pores may be prevented from crossing the graphenemembrane. The sensing device may be configured to identify a presence ofa selected molecule within the mixture without interference fromcontaminating factors.

The following definitions are intended to be general definitions forhelping the reader understand the disclosure. Any meanings impliedthroughout the specification are not intended to be limiting, but areintended to be example non-literal definitions for describing someexample embodiments.

As used herein, “graphene” may mean a planar allotrope of carboncharacterized by a hexagonal lattice of carbon atoms that may beconnected by aromatic carbon-carbon bonds. As used herein, a graphene“monolayer” may be a one-carbon atom thick layer of graphene. In someexamples, the graphene monolayer may include some nonaromatic carbons,e.g., some carbons may be passivated with hydrogen and may be bonded toother carbons by nonaromatic single carbon-carbon bonds. As used herein,a “perforated graphene monolayer” may mean a graphene monolayer that mayinclude a plurality of discrete pores through the graphene monolayer.The discrete pores may pass entirely through the graphene monolayer. Thediscrete pores may permit selective passage of atomic or molecularspecies from one side of the graphene monolayer to the other side of thegraphene monolayer. As used herein, a “chemically perforated” pore inthe graphene may be characteristic of preparation by selective removalof one or more carbon atoms from the graphene lattice, for example,atomic or molecular species may be reacted with the graphene in aprocess which results in selective removal of one or more carbon atomsfrom the graphene lattice.

As used herein, the “minimum steric separation” may mean the distancebetween the centers of adjacent discrete pores. For example, a minimumsteric separation corresponding to at least one interveningcarbon-carbon bond may be at least about 1 Angstrom. In some examples, aminimum steric separation corresponding to at least one interveningsix-membered graphene ring may be at least about 2.4 Angstroms. Invarious examples, a minimum steric separation may range from betweenabout 1 Angstrom to about 100 Angstroms, for example, at least about 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 12.5, 15, 20, 25, 35, or 50 Angstroms.

As used herein, “discrete” pores in a graphene monolayer may be distinctfrom each other by at least one intervening carbon-carbon bond, or insome examples, at least one intervening six-membered graphene ring. Forexample, two discrete pores may be separated from each other by at leastone intervening six-membered graphene ring or at least one interveningcarbon-carbon bond.

As used herein, a “carbon vacancy defect” may be a pore in a graphenemonolayer which may be defined by the absence of one or more carbonatoms compared to a graphene monolayer without a carbon vacancy defect.As used herein, the “number” of carbon vacancy defects in reference to“substantially the same number of one or more carbon vacancy defects”may mean about one or more carbon defects, or in some examples about twoor more carbon defects. In various examples, the number of carbonvacancy defects may be between about one and about ten defects, forexample, about: one, two, three, four, five, six, seven, eight, nine, orten defects.

As used herein, a “substantially uniform pore size” may mean that thediscrete pores may be characterized by substantially the same number ofone or more carbon vacancy defects per discrete pore. In variousexamples, discrete pores of substantially uniform pore size may havetheir carbon vacancy defects arranged in substantially the same relativelattice positions within each discrete pore. For example, a plurality ofsubstantially uniform pores that include six carbon vacancy defects eachmay correspond to removal of a six membered ring of carbon atoms in thehexagonal graphene lattice. In another example, a plurality ofsubstantially uniform pores that include six carbon vacancy defects eachmay correspond to removal of a six membered staggered linear chain ofcarbon atoms in the hexagonal graphene lattice.

As used herein, “substantially uniform pore sizes throughout” may meanthat at least about 80% of the discrete pores in a perforated graphenemonolayer may have a substantially uniform pore size. In variousexamples, the percentage of discrete pores in a perforated graphenemonolayer that may have a substantially uniform pore size may be: about85%, about 90%, about 95%, about 96%, about 97%, about 98%, about 99%,about 99.5%, or about 99.9%. In some examples, all of the discrete poresin a perforated graphene monolayer may have a substantially uniform poresize.

As used herein, “substantially the same number of one or more carbonvacancy defects” in relation to the plurality of discrete pores may meanthat such discrete pores differ from each other by at most about threecarbon vacancy defects. For example, a plurality of pores havingsubstantially the same number of one or more carbon vacancy defects mayrange between one and three carbon vacancy defects per pore. In variousexamples, discrete pores may vary in number of carbon vacancy defects byabout three, about two, or about one. In some examples, each of theplurality of discrete pores has the same number of carbon vacancydefects.

As used herein, “separation efficiency” may mean a ratio of perforatedgraphene membrane permeability rates between specific pairs of atomic ormolecular species. For example, the perforated graphene monolayer asdescribed below in conjunction with FIG. 1 and FIG. 2 may becharacterized by a hydrogen/methane separation efficiency, which may bea ratio of permeation rates of molecular hydrogen (H₂) compared tomethane (CH₄). In some examples, the hydrogen/methane separationefficiency may be at least about 200:1; or in various examples, betweenabout 200:1 and about 10²³:1, for example, at least about: 10³:1; 10⁴:1;10⁵:1; 10⁶:1; 10⁹:1; 10¹²:1; 10¹⁵:1; 10¹⁸:1; or 10²¹:1. Some exampleseparation efficiency theoretical calculations for a one-atom thickgraphene membrane characterized by pores 2.5 Angstroms in diameterprovide that the ratio of a calculated hydrogen permeability ratedivided by a calculated methane permeability rate is 10²³:1. Incomparison, currently known “solution diffusion” polymer membranes havea hydrogen to methane separation efficiency of about 150:1.

As used herein, a “permeable substrate” may be any material that may beemployed to provide support to a perforated graphene monolayer. As usedherein, a “permeable substrate” may also be permeable to at least oneatomic or molecular species that traverses discrete pores in theperforated graphene monolayer. Suitable substrates may include“solution-diffusion” solid membranes that permit atomic or molecularspecies to diffuse through the solid material of the permeablesubstrate. Suitable permeable substrates may also be configured asporous membranes or filters having pores, voids, channels, or the like,through which atomic or molecular species may travel. Suitable materialsfor the substrate may include, for example, one or more of SiO₂, SiC,Si, polyethylene, polypropylene, polyester, polyurethane, polystyrene,polyolefin, polysulfone and/or polyethersulfone. In various examples,suitable materials for the permeable substrate may be characterized by aminimum molecular weight cutoff from: about 1,000 Daltons to about1,000,000 Daltons; about 5,000 Daltons to about 1,000,000 Daltons; about25,000 Daltons to about 500,000 Daltons; about 50,000 Daltons to about250,000 Daltons; or about 100,000 Daltons. In some examples, a suitablepermeable substrate may include a polyether sulfone membranecharacterized by a maximum molecular weight cutoff of about 100,000Daltons.

As used herein, a “fluid mixture” may be any fluid phase, e.g., gasphase, liquid phase, or supercritical phase, which may include at leasta first molecular species and a second molecular species. In variousexamples, the fluid mixture may include: a mixture of gases; a mixtureof a vapor in a gas; a mixture of liquids; a solution of a gas dissolvedin a liquid; a solution of a solid dissolved in a liquid; a solution ofa gas, liquid or solid in a supercritical fluid; or the like. In someexamples, the fluid mixture may be in contact with other phases of thetwo or more different molecules. For example, a fluid mixture thatincludes fluid phase carbon dioxide as one of the molecules may be incontact with solid phase carbon dioxide.

FIG. 1 is a conceptual drawing of an example perforated graphenemonolayer, arranged in accordance with at least some embodimentsdescribed herein. Diagram 100 generally illustrates the hexagonallattice of carbon atoms 106 and aromatic bonds characteristic ofgraphene. The placement of the carbon-carbon double bonds in examplegraphene monolayers described herein, for example, in the graphenemonolayer 102, is intended to be illustrative of graphene and is notintended to be limiting.

The graphene monolayer 102 may be chemically perforated with a pluralityof discrete pores 108. The discrete pores 108 may be formed by theremoval of at least one carbon atom from a plurality of locations in thegraphene monolayer 102. The discrete pores 108 may have a substantiallyuniform pore size characterized by at least one carbon vacancy defect inthe graphene monolayer 102. In various examples, each discrete pore 108may include hydrogen-passivated carbon atoms 106. Diagram 100 also showsa minimum steric separation 104 between adjacent discrete pore 108locations in example graphene monolayer 102.

FIG. 2 illustrates an example graphene monolayer showing passivatedpores of the graphene monolayer, arranged in accordance with at leastsome embodiments described herein. Diagram 200 illustrates a graphenemonolayer 204 including a plurality of discrete pores 210. The discretepores 210 may be formed by selective removal of one or more carbon atoms202 from the hexagonal graphene lattice, causing a plurality of carbonvacancy defects, such that each discrete pore 210 in the graphenemonolayer 204 may be characterized by the absence of at least one carbonatom 202. The carbon atoms 202 may be removed employing one or more ofatomic oxygen etching, electron beam etching, or selective chemicaletching techniques. Other techniques may include UV-induced oxidativeetching, ion beam etching and/or lithographic masking coupled withoxygen plasma etching. In some examples, the remaining carbon atoms 202at the pore may be passivated with hydrogen atoms 206 to providestructural stability.

The discrete pores 210 may extend through the graphene monolayer 204such that the discrete pores 210 may permit selective passage of atomicor molecular species from one side of the graphene monolayer 204 to theother side of the graphene monolayer 204. Each of the discrete pores 210may have a substantially uniform pore size and may be characterized by arange of between about one carbon vacancy defect and about ten carbonvacancy defects. The discrete pores 210 of the graphene membrane may beof a selected size to provide a separation efficiency between a firstmolecular species and a second molecular species by enabling the passageof at least the first molecular species and preventing passage of thesecond molecular species. For example, the discrete pores 210 may have adiameter in a range from about 2 to about 3 Angstroms such that thediscrete pores 210 are selective for the passage of hydrogen.

FIG. 3 is a conceptual drawing of a side view of an example membraneillustrating a method of separating a gas mixture of two molecules,arranged in accordance with at least some embodiments described herein.Diagram 300 includes fluid mixture 304 that includes molecules 312, 314,graphene monolayer 306 that includes discrete pores 308, and substrate302.

An example membrane may be a perforated graphene monolayer 306. A fluidmixture 304 may include two or more molecules 312, 314 which may beexposed to the graphene monolayer 306 to separate the fluid mixture 304.The example perforated graphene monolayer 306 may include discrete pores308 configured to enable one or more of the molecules to pass throughthe discrete pores 308 to separate the molecules within the fluidmixture. The graphene monolayer 306 may be coupled with substrate 302 tosupport the graphene monolayer 306. The substrate 302 may be permeableor non-permeable. The graphene monolayer 306 may be coupled with thesubstrate 302 through an intermediate spacer, such as an insulatingframe and/or electrode contacts.

In diagram 300, the graphene monolayer 306 may be exposed to the fluidmixture 304 including first molecule 312, symbolized by dark-filledcircles, and second molecule 314, symbolized by white-filled circles.The first and second molecules may also include one or more differencesin atomic or chemical character such as differences in elementalcomposition, isotopic composition, molecular structure, size, mass,hydrophobicity, polarity, polarizability, charge distribution, or thelike. For example, the first molecule 312 may be smaller than the secondmolecule 314 as symbolized by the relative sizes of the filled circlesin FIG. 3. In some examples, discrete pores such as 308 may becharacterized by a diameter that may be selective for passage of thefirst molecule compared to the second molecule. The diameter of eachpore may be selective for passage of first molecule 312 compared tosecond molecule 314 based on the one or more differences in atomic orchemical character, e.g., size. In some examples, the graphene monolayer306 may be selective for the passage of hydrogen such that the graphenemonolayer 306 may be characterized by a hydrogen/methane separationefficiency. The diameter may be about 2.5 Angstroms for enabling thepassage of hydrogen through the discrete pores 308. In some examples,the diameter may be up to about 10 Angstroms for enabling separation ofHydrogen from other gases.

As demonstrated in diagram 300, the fluid mixture of molecules 312 and314 may be contacted to the graphene monolayer 306, and the firstmolecule 312 may be directed through the discrete pores 308 to separatethe first molecule 312 from the second molecule 314. The first molecule312 may be directed through discrete pores 308 by imposing a gradient ordifferential across the graphene monolayer in a property that may causethe molecule to move through the discrete pores. The gradient ordifferential may include differences in one or more properties such astemperature, pressure, concentration, or electrochemical potential. Forexample, a temperature gradient may be established by heating or coolingmolecules on one side of the membrane compared to the other side of themembrane. Similarly, a pressure gradient may be established bypressurizing or depressurizing one side of the membrane compared to theother side. A concentration gradient may be established, for example, byholding a mixture of gases to be separated on one side of the membrane,e.g., hydrogen and methane, and removing the desired molecule, e.g.,hydrogen, from the other side of the membrane as it traverses themembrane. An electrochemical gradient may be established by using themembrane as a cell separator in an electrochemical cell, for example,separating the cathode and anode in water to hydrogen and oxygenelectrolysis cell.

The first and second molecules may include compounds consisting of asingle atom, for example, helium, neon, argon, krypton, xenon, andradon. The molecules may also include compounds of two or more atomsconnected by one or more covalent bonds, ionic bonds, coordinationbonds, or the like. For example, suitable molecules may include water,hydrogen, nitrogen, oxygen, carbon monoxide, carbon dioxide, sulfurdioxide, hydrogen sulfide, a nitrogen oxide, a C1-C4 alkane, a silane,or a haloacid.

In some examples, the second molecule may be a liquid, e.g., water or anorganic solvent, and the first molecule may be a covalent or ionicmolecular compound dissolved in the liquid. In some examples, onemolecule may be a polar liquid such as water, and the other molecule maybe a salt that includes a cation and an anion. Examples of cations forsalts may include metal cations, e.g., alkali metal cations such aslithium, sodium, potassium, or the like; alkali earth metal cations suchas calcium or magnesium, or the like; cations of transition metals suchas copper, iron, nickel, zinc, manganese, or the like; cations of metalsin other groups, such as cations of aluminum; and so on. Examples ofanions for salts may include, but are not limited to, fluoride,chloride, bromide, iodide, chlorate, bromate, iodate, perchlorate,perbromate, periodate, hydroxide, carbonate, bicarbonate, sulfate,phosphate, and so on. In some examples, the fluid mixture may be anatural water source such as seawater or groundwater, where theperforated graphene membrane may be employed to separate water fromnatural solutes, such as sodium chloride, and/or unnatural solutes, suchas molecules that are manmade pollutants.

FIG. 4 is a conceptual drawing of a side view of an example membranethat includes an example perforated graphene monolayer in contact with asensing device and a permeable substrate configured to detect a gasmolecule in a gas mixture, arranged in accordance with at least someembodiments described herein. Diagram 400 includes fluid mixture 404that includes molecules 412, 414, graphene monolayer 406 that includesdiscrete pores 408, insulating frame 410, electrode contacts 416,sensing device 402, and substrate 420.

As illustrated in diagram 400, a membrane may be provided for separatinga fluid mixture 404 including two or more molecules 412, 414. Themembrane may be a graphene monolayer 406, which may be perforated with aplurality of discrete pores 408. The discrete pores 408 may permit oneor more of the molecules to cross the graphene monolayer 406 through thediscrete pores 408 to separate the molecules 412, 414 of the fluidmixture 404. A sensing device 402 may be provided to detect the presenceof one or more molecules that cross the graphene monolayer 406. Apermeable substrate 420 may be coupled to the sensing device 402 and thegraphene monolayer 406 for support. The sensing device 402 may becoupled with the graphene monolayer 406 by insulating frame 410 andelectrode contacts 416. The sensing device may be bonded to thesubstrate through non-covalent interactions, such as van der Waalsforces, through adhesive interactions, such as via epoxy, pressuresensitive adhesive, or other bonding agents, and also employingmechanical fixation, for example by compressing the edges of themembrane to the substrate using a frame.

As illustrated in diagram 400, the sensing device 402 may be configuredto detect a presence of one or more molecules that permeate the graphenemonolayer 406. When the sensing device 402 is used to detect thepresence of a selected molecule, the sensing device 402 may be subjectto contamination from factors temperature, humidity, and contaminatingmolecules that reduce the sensitivity of the sensing device 402. Thesensing device 402 may be coupled with the graphene monolayer 406 toprotect the sensing device 402 from contamination due to variousfactors. The graphene monolayer 406 may protect the sensing device 402from contamination by inhibiting the passage of molecules of a selectedsize across the graphene monolayer 406 such that certain molecules areprevented from contacting the sensing device 402. In order to inhibitlarger contaminating molecules from contacting the sensing device 402,the graphene monolayer 406 may be perforated with a plurality ofdiscrete pores 408 that may enable the passage of molecules of aselected size across the graphene monolayer 406 while inhibiting thepassage of larger molecules. For example, the discrete pores may be of asize to provide size-selective access of a first molecule 412 having adiameter less than a diameter of the discrete pore 408, but not thesecond molecule 414 having a diameter greater than a diameter of thediscrete pore 408.

In an example embodiment, the discrete pores 408 of the graphenemonolayer 406 may have a size-selective to pass small molecules acrossthe graphene monolayer, such that the sensing device may detect thepresence of the small molecules as they cross the graphene monolayer 406by passing through the discrete pores 408. For example, the discretepores 408 may be of a selected size for enabling the passage of hydrogensuch that the graphene monolayer 406 may be characterized by aselectivity for hydrogen. The graphene monolayer 406 may also becharacterized by a selectivity for other small molecules includinghelium, neon, argon, xenon, krypton, radon, hydrogen, nitrogen, oxygen,carbon monoxide, carbon dioxide, sulfur dioxide, hydrogen sulfide, anitrogen oxide, a C1-C4 alkane, a silane, or a haloacid.

In some examples, the sensing device 402 may be configured to detect thepresence of hydrogen. Methane may be an example contaminating moleculein the detection of hydrogen by the sensing device 402. The graphenemonolayer 406 may be characterized by a hydrogen/methane separationefficiency to enable the sensing device 402 to detect the presence ofhydrogen without contamination due to the presence of methane. Thediscrete pores 408 may be of a selected size for enabling the passage ofhydrogen across the graphene monolayer 406 while preventing the passageof methane. For example, the discrete pores 408 may have a diameter ofabout 2.5 Angstroms such that the discrete pores 408 are selective forthe passage of hydrogen.

In some examples, the sensing device 402 may be selected from one ormore of a metal-oxide sensor, a non-metal oxide sensor, a catalyticsensor, an optical sensor, or an electrochemical sensor configured todetect the presence of a selected molecule. The sensing device 402 mayalso be selected from one or more of, a resistance-based, thermallyconductive, work function-based, mechanical, and/or acoustic sensor. Insome examples, the sensing device 402 may be a rigid graphene sensorconfigured to detect the presence of hydrogen. Palladium nanoparticlesmay be deposited on the rigid graphene sensor to increase thesensitivity to identify the presence of hydrogen. The rigid graphenesensor may be coupled to the permeable substrate which may support therigid graphene sensor. In other examples, the rigid sensor may beaffixed within a depressed portion of the substrate. In an exampleembodiment, a portion of the surface of the substrate may be depressedsuch that a cavity is formed on the surface of the substrate. The sensormay be positioned within the cavity such that when the sensor is inposition, the sensor may not extend beyond the surface of the substrate.

In an example scenario, the presence of a selected molecule in a fluidmixture may be detected as described hereafter. The fluid mixture 404 ofmolecules 412 and 414 may be exposed to the graphene monolayer 406. Thefirst molecule 412 may be passed through the discrete pores 408 toseparate the first molecule 412 from the second molecule 414, and toenable the sensing device to detect the presence of the first molecule412 without contamination from the second molecule 414. The firstmolecule 412 may pass through the discrete pores 408 by an imposedgradient across the graphene monolayer 406. The gradient may includedifferences in one or more properties such as temperature, pressure,concentration, polarity, or electrochemical potential. As the firstmolecule 412 passes the graphene monolayer 406 through the discretepores 408, the sensing device 402 may detect the first molecule 412 andidentify the presence of the first molecule 412.

FIG. 5 is a block diagram of an automated system that may be used formaking an example gas filtration and detection device, arranged inaccordance with at least some embodiments described herein.

System 500 may include a manufacturing controller 520, a graphene source522, a sample manipulator 524, graphene perforation apparatus 526, ahydrogen passivation source, 528, a substrate source 530, a sensingdevice applicator 532, an electrode applicator 534, and a cavityapparatus 536.

As illustrated in system 500, a gas filtration and detection device maybe manufactured to filter a fluid mixture and detect molecules thatcross the graphene membrane. The manufacturing controller 520 may becoupled to machines that can be used to carry out steps formanufacturing the gas filtration and detection device including thegraphene membrane and the sensing device, for example, the graphenesource 522 to provide the graphene membrane and the substrate source 530to provide a substrate and sensing device. The manufacturing controller520 may be operable to configure the sample manipulator 524, grapheneperforation apparatus 526, and hydrogen passivation source associatedwith the graphene source 522 to facilitate the formation of the graphenemonolayer that includes a plurality of discrete pores. The manufacturingcontroller 520 may also be operable to configure a sensing deviceapplicator 532, the electrode applicator 534, and the cavity apparatus536 to facilitate contacting the graphene monolayer with a sensingdevice and a supporting substrate.

The manufacturing controller 520 may also configure the samplemanipulator 524 to support the graphene monolayer during a process offorming the discrete pores in the graphene monolayer. The manufacturingcontroller 520 may also configure the graphene perforation apparatus 526to facilitate formation of discrete pores in the graphene monolayer. Thegraphene perforation apparatus 526 may employ one or more of atomicoxygen etching, electron beam etching, or selective chemical etching forremoving one or more carbon atoms from a plurality of locations withinthe carbon nanotubes causing a plurality of carbon vacancy defects inthe carbon nanotubes. The manufacturing controller 520 may alsoconfigure the hydrogen passivation source 528 to facilitate passivatingcarbon atoms remaining at the one or more carbon vacancy defects in thegraphene monolayer with hydrogen.

After forming the graphene monolayer with a plurality of discrete pores,the gas filtration and detection device, which includes the sensingdevice may be manufactured. The substrate source may provide a substrateon which a sensing device may be attached. The substrate may bepermeable or non-permeable. The sensing device applicator 532 mayprovide the sensing device to couple the sensing device with thepermeable substrate. In some examples, a cavity apparatus 536 may form acavity in the permeable substrate by carving out a portion of thesurface of the substrate such that the carved out portion is depressedand forms a cavity. The sensing device applicator 532 may affix thesensing device within the cavity formed in the permeable substrate. Thesubstrate source 530 and the graphene source 522 may contact thegraphene monolayer with the substrate and attached sensing device. Theelectrode applicator 534 may provide electrode contacts and aninsulating frame for contacting the sensing device and substrate withthe graphene monolayer.

FIG. 6 illustrates a general purpose computing device that may be usedto control the automated system of FIG. 5 or similar manufacturingequipment in making an example membrane, arranged in accordance with atleast some embodiments described herein. In a basic configuration 602,computing device 600 may include one or more processors 604 and a systemmemory 606. A memory bus 608 may be used for communicating betweenprocessor 604 and system memory 606.

Depending on the desired configuration, processor 604 may be of any typeincluding but not limited to a microprocessor (μP), a microcontroller(μC), a digital signal processor (DSP), or any combination thereof.Processor 604 may include one or more levels of caching, such as a cachememory 612, a processor core 614, and registers 616. Example processorcore 614 may include an arithmetic logic unit (ALU), a floating pointunit (FPU), a digital signal processing core (DSP core), or anycombination thereof. An example memory controller 618 may also be usedwith processor 604, or in some implementations, memory controller 615may be an internal part of processor 604.

Depending on the desired configuration, system memory 606 may be of anytype including but not limited to volatile memory (such as RAM),non-volatile memory (such as ROM, flash memory, etc.) or any combinationthereof. System memory 606 may include an operating system 620, one ormore manufacturing control applications 622, and program data 624.Manufacturing control application 622 may include a control module 626that may be arranged to control automated system of FIG. 5 and any otheroperations, functions or actions processes, methods and operations asdiscussed above. Program data 624 may include, among other data,material data 628 for controlling various aspects of the automatedmachine in system 500. This described basic configuration 602 isillustrated in FIG. 6 by those components within the inner dashed line.

Computing device 600 may have additional features or functionality, andadditional interfaces to facilitate communications between basicconfiguration 602 and any devices and interfaces. For example, abus/interface controller 630 may be used to facilitate communicationsbetween basic configuration 602 and one or more data storage devices 632via a storage interface bus 634. Data storage devices 632 may beremovable storage devices 636, non-removable storage devices 638, or acombination thereof. Examples of removable storage and non-removablestorage devices include magnetic disk devices such as flexible diskdrives and hard-disk drives (HDDs), optical disk drives such as compactdisk (CD) drives or digital versatile disk (DVD) drives, solid statedrives (SSDs), and tape drives to name a few. Example computer storagemedia may include volatile and non-volatile, removable and non-removablemedia implemented in any method or technology for storage ofinformation, such as computer readable instructions, data structures,program modules, or other data.

System memory 606, removable storage devices 636 and non-removablestorage devices 638 may be examples of computer storage media. Computerstorage media may include, but is not limited to, RAM, ROM, EEPROM,flash memory or other memory technology, CD-ROM, digital versatile disks(DVD) or other optical storage, magnetic cassettes, magnetic tape,magnetic disk storage or other magnetic storage devices, or any othermedium which may be used to store the desired information and which maybe accessed by computing device 600. Any such computer storage media maybe part of computing device 600.

Computing device 600 may also include an interface bus 640 forfacilitating communication from various interface devices (e.g., outputdevices 642, peripheral interfaces 644, and communication devices 666)to basic configuration 602 via bus/interface controller 630. Exampleoutput devices 642 may include a graphics processing unit 648 and anaudio processing unit 650, which may be configured to communicate tovarious external devices such as a display or speakers via one or moreA/V ports 652. Example peripheral interfaces 544 may include a serialinterface controller 654 or a parallel interface controller 656, whichmay be configured to communicate with external devices such as inputdevices (e.g., keyboard, mouse, pen, voice input device, touch inputdevice, etc.) or other peripheral devices (e.g., printer, scanner, etc.)via one or more I/O ports 658. An example communication device 666 mayinclude a network controller 660, which may be arranged to facilitatecommunications with one or more other computing devices 662 over anetwork communication link via one or more communication ports 664.

The network communication link may be one example of a communicationmedia. Communication media may be embodied by computer readableinstructions, data structures, program modules, or other data in amodulated data signal, such as a carrier wave or other transportmechanism, and may include any information delivery media. A “modulateddata signal” may be a signal that has one or more of its characteristicsset or changed in such a manner as to encode information in the signal.By way of example, and not limitation, communication media may includewired media such as a wired network or direct-wired connection, andwireless media such as acoustic, radio frequency (RF), microwave,infrared (IR) and other wireless media. The term computer readable mediaas used herein may include both storage media and communication media.

Computing device 600 may be implemented as a portion of a physicalserver, virtual server, a computing cloud, or a hybrid device that mayinclude any of the above functions. Computing device 600 may also beimplemented as a personal computer including both laptop computer andnon-laptop computer configurations. Moreover computing device 600 may beimplemented as a networked system or as part of a general purpose orspecialized server.

Networks for a networked system including computing device 600 maycomprise any topology of servers, clients, switches, routers, modems,Internet service providers, and any appropriate communication media(e.g., wired or wireless communications). A system according toembodiments may have a static or dynamic network topology. The networksmay include a secure network such as an enterprise network (e.g., a LAN,WAN, or WLAN), an unsecure network such as a wireless open network(e.g., IEEE 602.11 wireless networks), or a world-wide network such(e.g., the Internet). The networks may also comprise a plurality ofdistinct networks that may be adapted to operate together. Such networksmay be configured to provide communication between the nodes describedherein. By way of example, and not limitation, these networks mayinclude wireless media such as acoustic, RF, infrared and other wirelessmedia. Furthermore, the networks may be portions of the same network orseparate networks.

FIG. 7 is a flow diagram illustrating a method that may be used todetect a gas molecule that crosses a graphene membrane, arranged inaccordance with at least some embodiments described herein.

Example methods may include one or more operations, functions or actionsas illustrated by one or more of blocks 722, 724, 726 and/or 728. Theoperations described in blocks 722 through 728 may also be stored ascomputer-executable instructions in a computer-readable medium such ascomputer-readable medium 720 of computing device 710.

A process of detecting a gas molecule that crosses a graphene membranemay begin with block 722, “EXPOSE A FLUID MIXTURE TO A GRAPHENEMEMBRANE, WHICH INCLUDES DISCRETE PORES.” At block 722, a fluid mixture404 may be exposed to a graphene membrane 406, such that the fluidmixture 404 may be brought into contact with the graphene membrane 406.The fluid mixture 404 may be a mixture in a gas phase, liquid phase, orsupercritical phase, and may include two or more distinct molecularspecies which may be separated based on properties of each species, suchas size. For example, the fluid mixture 404 may include two or moremolecules such that a first molecule 412 may be smaller than a secondmolecule 414. The graphene membrane 406 may be a graphene monolayer,which includes a plurality of discrete pores 408 having a size-selectivefor the passage of the first smaller gas molecule but not the secondlarger gas molecule.

Block 722 may be followed by block 724, “SELECTIVELY PERMEATE A MOLECULETHROUGH THE GRAPHENE MEMBRANE.” When the fluid mixture 404 is exposed toand brought into contact with the graphene membrane 406, the firstmolecule 412 may be directed through the plurality of discrete pores 408such that the first molecule may be separated from the second molecule414. The first molecule 412 may be smaller than the diameter of thediscrete pores 408 such that the first molecule 412 may pass through thediscrete pores 408. The second molecule 414 may be larger than thediameter of the discrete pores 408 such that the second molecule may beprevented from crossing the graphene membrane through the discretepores.

Block 724 may be followed by block 726, “DETECT MOLECULE WITH A SENSINGDEVICE.” A sensing device 402 may be coupled with the graphene membrane406 in order to detect first molecule 412 when it crosses the graphenemembrane 406 through the discrete pores 408. The sensing device 402 maybe supported by a permeable substrate 420 and coupled with the graphenemembrane by one or more electrode contacts 416 and/or an insulatingframe 410.

Block 726 may be followed by block 728, “IDENTIFY PRESENCE OF MOLECULEWITH THE SENSING DEVICE.” The sensing device 402 may be configured toidentify a presence of the first molecule 412 that crosses the graphenemembrane 406 through the discrete pores 408. In some examples, thesensing device 402 may be a rigid graphene sensor, and the rigidgraphene sensor may be deposited with palladium nanoparticles in orderto detect the presence of hydrogen.

FIG. 8 illustrates a block diagram of an example computer programproduct that may be used to control the automated machine of FIG. 5 orsimilar manufacturing equipment in making an example membrane, arrangedin accordance with at least some embodiments described herein. In someexamples, as shown in FIG. 8, computer program product 800 may include asignal bearing medium 802 that may also include machine readableinstructions 804 that, when executed by, for example, a processor, mayprovide the functionality described above with respect to FIG. 6 andFIG. 7. Thus, for example, referring to processor 604, the controlmodule 626 may undertake one or more of the tasks shown in FIG. 8 inresponse to instructions 804 conveyed to processor 604 by signal bearingmedium 802 to perform actions associated with filtering a fluid mixturethrough a gas filtration device including a plurality of carbonnanotubes as described herein. Some of those instructions may includeproviding a fluid mixture to a graphene membrane including discretepores providing size-selective access of gas molecules, contacting thefluid mixture to the graphene membrane, selectively permeating amolecule through the graphene membrane, providing a sensing deviceconfigured to detect the molecule, and detecting a presence of themolecule at the sensing device.

In some implementations, signal bearing medium 802 depicted in FIG. 8may encompass a computer-readable medium 806, such as, but not limitedto, a hard disk drive (HDD), a Compact Disc (CD), a Digital VersatileDisk (DVD), a digital tape, memory, etc. In some implementations, signalbearing medium 802 may encompass a recordable medium 808, such as, butnot limited to, memory, read/write (R/W) CDs, R/W DVDs, etc. In someimplementations, signal bearing medium 802 may encompass acommunications medium 810, such as, but not limited to, a digital and/oran analog communication medium (e.g., a fiber optic cable, a waveguide,a wired communication link, a wireless communication link, etc.). Thus,for example, computer program product 800 may be conveyed to one or moremodules of the processor 504 by an RF signal bearing medium 802, wherethe signal bearing medium 802 is conveyed by a wireless communicationsmedium 810 (e.g., a wireless communications medium conforming with theIEEE 802.11 standard).

According to some examples embodiments, the present disclosure describesa gas detection device. The gas detection device may include asubstrate, a sensing device coupled to the substrate, the sensing deviceconfigured to detect a presence of one or more gases, and a graphenemembrane coupled to the sensing device, the graphene membrane includinga plurality of discrete pores having a size-selective to pass of the oneor more gases across the graphene membrane such that the sensing devicemay be operable to detect the presence of the one or more gases.

According to some examples, the graphene membrane may include a graphenemonolayer with the plurality of discrete pores having a substantiallyuniform pore size. Each pore in the plurality of discrete pores may becharacterized by at least one carbon vacancy defect in the graphenemonolayer. Each pore in the plurality of discrete pores may becharacterized by two or more carbon vacancy defects in the graphenemonolayer.

According to some examples, the graphene monolayer may be characterizedby selectivity to H₂. The graphene monolayer may be characterized by aseparation selectivity of H₂:CH₄ of at least 200:1. The plurality ofdiscrete pores may be characterized by a minimum separation of at leastabout 2.5 Angstroms. Carbon vacancy defects in the graphene monolayermay be passivated with hydrogen.

According to some examples, the substrate may include one or more of apolyethylene, polypropylene, polyester, polyurethane, polystyrene,polysulfone, polyethersulfone, SiO₂, SiC, and/or Si substrate. Thesensing device may be one of a: metal-oxide, non-metal oxide, catalytic,optical, resistance-based, thermally conductive, work function-based,mechanical, acoustic, and electrochemical sensor configured to detectthe presence of H₂. The sensing device may be a rigid graphene sensor,where the graphene sensor may be deposited with palladium nanoparticlesfor detecting the presence of H₂.

According to some examples, the graphene monolayer may be coupled to thesensing device by an insulating frame. The graphene monolayer may becoupled to the sensing device by one or more electrode contacts. Thegraphene monolayer may be coupled to the sensing device by one or moreelectrode contacts through an insulating frame.

According to other example embodiments, the present disclosure alsodescribes a method of detecting a gas molecule in a fluid mixtureincluding one or more gases. The method may include exposing the fluidmixture, which includes at least a first gas molecule and a second gasmolecule to a graphene membrane such that the fluid mixture may bebrought in contact with the graphene membrane, where the graphenemembrane includes including a plurality of discrete pores having asize-selective for the passage of the first gas molecule but not thesecond gas molecule, selectively permeating the first gas moleculethrough the discrete pores of the graphene membrane, detecting the firstgas molecule with a sensing device, and identifying the presence of thefirst gas molecule with sensing device.

According to some examples, the method may also include exposing thefluid mixture to a graphene monolayer, where the plurality of discretepores may be formed in the graphene monolayer to cause one or morecarbon vacancy defects in the graphene monolayer such that the graphenemonolayer has substantially uniform pore sizes throughout.

According to other examples, the method may also include exposing thefluid mixture to the graphene monolayer such that there may be selectivepassage of H₂ across the graphene monolayer. Selectively permeating thefirst gas molecule through the discrete pores of the graphene membranemay also include permeating the first gas molecule through the pluralityof discrete pores by employing a gradient across the graphene monolayer.Selectively permeating the first gas molecule through the discrete poresof the graphene membrane may also include permeating the first gasmolecule through the plurality of discrete pores by employing one ormore of a temperature, pressure, concentration, polarity, orelectrochemical potential gradient across the graphene monolayer.

According to other examples, the method may also include separating thefirst gas molecule from the second gas molecule of the fluid mixture ata separation selectivity of H₂:CH₄ of at least 200:1. Detecting thefirst gas molecule with the sensing device may also include detectingone or more of helium, neon, argon, xenon, krypton, radon, hydrogen,nitrogen, oxygen, carbon monoxide, carbon dioxide, sulfur dioxide,hydrogen sulfide, a nitrogen oxide, a C1-C4 alkane, a silane, or ahaloacid at the sensing device.

According to further example embodiments, the present disclosure alsoincludes a method of forming a gas detection device. The method mayinclude providing a substrate to provide support a sensing device and agraphene membrane, coupling the sensing device with the substrate, wherethe sensing device may be operable to detect a presence of one or moregases included in a fluid mixture, and coupling the graphene membranewith the sensing device, where the graphene membrane includes aplurality of discrete pores having a size-selective for the passage ofthe one or more gases across the graphene membrane for detection by thesensing device.

According to some examples, the method may also include forming thegraphene membrane from a graphene monolayer with the plurality ofdiscrete pores having a substantially uniform pore size. The method mayalso include forming the plurality of discrete pores in the graphenemonolayer by removing graphene carbon atoms from a plurality oflocations within the graphene monolayer, where the plurality of discretepores may be characterized by a plurality of carbon vacancy defects inthe graphene monolayer such that the graphene monolayer hassubstantially uniform pore sizes throughout. The method may also includeforming the plurality of discrete pores in the graphene monolayer bycausing one or more carbon vacancy defects in the graphene monolayersuch that the plurality of discrete pores may be characterized by adiameter that may be selective for passage of H₂.

According to some examples, the method may also include passivating theone or more carbon vacancy defects in the graphene monolayer withhydrogen. Coupling the sensing device with the substrate may alsoinclude selecting the substrate from one or more of polyethylene,polypropylene, polyester, polyurethane, polystyrene, polysulfone,polyethersulfone, SiO₂, SiC, and/or Si substrate. The method may alsoinclude selecting the sensing device from one or more of: a metal-oxide,non-metal oxide, catalytic, optical, resistance-based, thermallyconductive, work function-based, mechanical, acoustic, andelectrochemical sensor. Coupling a graphene membrane with the sensingdevice may also include coupling the graphene membrane with the sensingdevice by an insulating frame.

According to some examples, coupling a graphene membrane with thesensing device further may also include coupling the graphene membranewith the sensing device by one or more electrode contacts. Coupling thesensing device with the substrate may further include positioning thesensing device within a depressed portion of the substrate. Coupling thesensing device with the substrate may also include forming the sensingdevice from a rigid graphene sensor. Coupling the sensing device withthe substrate may further include depositing the rigid graphene sensorwith Palladium particles for detecting the presence of H₂ at the sensingdevice.

According to yet other example embodiments, the present disclosure alsodescribes a system for manufacturing a gas detection device. The systemmay include a controller configured by instructions stored thereon tofacilitate manufacturing of the gas detection device employing agraphene source, a substrate source, and a sensing device applicator.The controller may be operable to configure the graphene source toprovide a graphene membrane, where the graphene membrane includes aplurality of discrete pores having a size-selective for the passage ofone or more gases included in a fluid mixture across the graphenemembrane, configure the substrate source to provide a substrate tosupport the graphene membrane, and configure the sensing deviceapplicator to contact a sensing device with the substrate, the sensingdevice configured to detect a presence of the one or more gasescontained in the fluid mixture that cross the graphene membrane.

According to some examples, the controller may be further operable toconfigure a sample manipulator to support formation of the graphenemembrane from a graphene monolayer with the plurality of discrete poreshaving a substantially uniform pore size. The controller may be furtheroperable to configure a graphene perforation apparatus to form theplurality of discrete pores in the graphene monolayer by removinggraphene carbon atoms from a plurality of locations within the graphenemonolayer, where the plurality of discrete pores may be characterized bya plurality of carbon vacancy defects in the graphene monolayer suchthat the graphene monolayer has substantially uniform pore sizesthroughout. The graphene perforation apparatus may be further configuredto form the plurality of discrete pores in the graphene monolayer bycausing one or more carbon vacancy defects in the graphene monolayersuch that the plurality of discrete pores may be characterized by adiameter that may be selective for passage of H₂.

According to some examples, the controller may be further operable toconfigure a hydrogen passivation source to passivate the one or morecarbon vacancy defects in the graphene monolayer with hydrogen. Thesubstrate source may be further configured to provide one or more of apolyethylene, polypropylene, polyester, polyurethane, polystyrene,polysulfone, polyethersulfone, SiO₂, SiC, and/or Si substrate. Thesensing device applicator may be further configured to couple one ormore of: a metal-oxide, non-metal oxide, catalytic, optical,resistance-based, thermally conductive, work function-based, mechanical,acoustic, and electrochemical sensor with the substrate. The controllermay be further operable to configure a cavity apparatus to form cavitydepressed cavity area on a surface of the substrate and position thesensing device within the cavity formed in the substrate.

According to some examples, the sensing device applicator may be furtherconfigured to couple a rigid graphene sensor with the substrate. Thesensing device applicator may be further configured to deposit the rigidgraphene sensor with palladium nanoparticles to detect the presence ofH₂ to the substrate. The controller may be further operable to configurean electrode applicator to couple the rigid graphene sensor with thesubstrate by an insulating frame and electrode contacts.

There is little distinction left between hardware and softwareimplementations of aspects of systems; the use of hardware or softwareis generally (but not always, in that in certain contexts the choicebetween hardware and software may become significant) a design choicerepresenting cost vs. efficiency tradeoffs. There are various vehiclesby which processes and/or systems and/or other technologies describedherein may be effected (e.g., hardware, software, and/or firmware), andthat the preferred vehicle will vary with the context in which theprocesses and/or systems and/or other technologies are deployed. Forexample, if an implementer determines that speed and accuracy areparamount, the implementer may opt for a mainly hardware and/or firmwarevehicle; if flexibility is paramount, the implementer may opt for amainly software implementation; or, yet again alternatively, theimplementer may opt for some combination of hardware, software, and/orfirmware.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples may be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. In one embodiment,several portions of the subject matter described herein may beimplemented via Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs), orother integrated formats. However, those skilled in the art willrecognize that some aspects of the embodiments disclosed herein, inwhole or in part, may be equivalently implemented in integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g. as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and/or firmwarewould be well within the skill of one of skill in the art in light ofthis disclosure.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

In addition, those skilled in the art will appreciate that themechanisms of the subject matter described herein are capable of beingdistributed as a program product in a variety of forms, and that anillustrative embodiment of the subject matter described herein appliesregardless of the particular type of signal bearing medium used toactually carry out the distribution. Examples of a signal bearing mediuminclude, but are not limited to, the following: a recordable type mediumsuch as a floppy disk, a hard disk drive (HDD), a Compact Disc (CD), aDigital Versatile Disk (DVD), a digital tape, a computer memory, etc.;and a transmission type medium such as a digital and/or an analogcommunication medium (e.g., a fiber optic cable, a waveguide, a wiredcommunication link, a wireless communication link, etc.).

Those skilled in the art will recognize that it is common within the artto describe devices and/or processes in the fashion set forth herein,and thereafter use engineering practices to integrate such describeddevices and/or processes into data processing systems. That is, at leasta portion of the devices and/or processes described herein may beintegrated into a data processing system via a reasonable amount ofexperimentation. Those having skill in the art will recognize that atypical data processing system generally includes one or more of asystem unit housing, a video display device, a memory such as volatileand non-volatile memory, processors such as microprocessors and digitalsignal processors, computational entities such as operating systems,drivers, graphical user interfaces, and applications programs, one ormore interaction devices, such as a touch pad or screen, and/or controlsystems including feedback loops and control motors (e.g., feedback forsensing position and/or velocity of gantry systems; control motors formoving and/or adjusting components and/or quantities).

A typical data processing system may be implemented utilizing anysuitable commercially available components, such as those typicallyfound in data computing/communication and/or networkcomputing/communication systems. The herein described subject mattersometimes illustrates different components contained within, orconnected with, different other components. It is to be understood thatsuch depicted architectures are merely exemplary, and that in fact manyother architectures may be implemented which achieve the samefunctionality. In a conceptual sense, any arrangement of components toachieve the same functionality is effectively “associated” such that thedesired functionality is achieved. Hence, any two components hereincombined to achieve a particular functionality may be seen as“associated with” each other such that the desired functionality isachieved, irrespective of architectures or intermediate components.Likewise, any two components so associated may also be viewed as being“operably connected”, or “operably coupled”, to each other to achievethe desired functionality, and any two components capable of being soassociated may also be viewed as being “operably couplable”, to eachother to achieve the desired functionality. Specific examples ofoperably couplable include but are not limited to physically connectableand/or physically interacting components and/or wirelessly interactableand/or wirelessly interacting components and/or logically interactingand/or logically interactable components.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation, no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations).

Furthermore, in those instances where a convention analogous to “atleast one of A, B, and C, etc.” is used, in general, such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, and C”would include but not be limited to systems that have A alone, B alone,C alone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeinclude the number recited and refer to ranges which can be subsequentlybroken down into subranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember. Thus, for example, a group having 1-3 cells refers to groupshaving 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers togroups having 1, 2, 3, 4, or 5 cells, and so forth.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

What is claimed is:
 1. A gas detection device, comprising: a substrate,wherein a portion of a surface of the substrate is depressed to form acavity in the surface of the substrate; a sensor device comprising arigid graphene sensor deposited with palladium nanoparticles, whereinthe sensor device: is coupled to the substrate and positioned within thecavity, is confined below the surface of the substrate by beingpositioned within the cavity, is configured to detect a presence ofhydrogen, and has a sensitivity, to detect the presence of the hydrogen,that is reduced in response to the sensor device being subjected tocontamination from methane; and a graphene membrane coupled to thesensor device by at least one of an insulation frame and one or moreelectrode contacts, wherein: the graphene membrane includes a graphenemonolayer with a plurality of discrete pores having a size-selectivitybased on a diameter of each of the plurality of discrete pores forpassage of the hydrogen across the graphene membrane for detection bythe sensor device, and having the size-selectivity for inhibition ofpassage of the methane across the graphene membrane so as to restrictthe methane from contact with the sensor device and thus to protect thesensor device from the contamination that reduces the sensitivity of thesensor device to detect the presence of the hydrogen, the diameter ofeach of the plurality of discrete pores of the graphene membrane is 2.5Angstroms, and a hydrogen and methane separation selectivity of thegraphene membrane is 10^23:1 based on the diameter of each of theplurality of discrete pores, the hydrogen is selectively permeatedthrough the discrete pores of the graphene monolayer by employment of agradient across the graphene monolayer, and the gradient includes one ormore of a temperature gradient, a pressure gradient, a concentrationgradient, a polarity gradient, and an electrochemical potentialgradient.
 2. The gas detection device of claim 1, wherein the pluralityof discrete pores have a uniform pore size.
 3. The gas detection deviceof claim 2, wherein each pore in the plurality of discrete poresincludes eat least one carbon vacancy defect in the graphene monolayer.4. The gas detection device of claim 2, wherein each pore in theplurality of discrete pores includes two or more carbon vacancy defectsin the graphene monolayer.
 5. The gas detection device of claim 2,wherein carbon vacancy defects in the graphene monolayer are passivatedwith hydrogen.
 6. The gas detection device of claim 1, wherein thesubstrate includes one or more of a polyethylene, polypropylene,polyester, polyurethane, polystyrene, polysulfone, polyethersulfone,SiO₂, SiC, and/or Si substrate.
 7. The gas detection device of claim 1,wherein the sensor device is selected from one of a: metal-oxide,non-metal oxide, catalytic, optical, resistance-based, thermallyconductive, work function-based, mechanical, acoustic, andelectrochemical sensor configured to detect the presence of hydrogen. 8.A system to manufacture a gas detection device, the system comprising: acontroller communicatively coupled to a graphene source that provides agraphene membrane, a substrate source that provides a substrate, and asensor device applicator, wherein the controller is configured to:instruct the graphene source to provide the graphene membrane, wherein:the graphene membrane includes a graphene monolayer with a plurality ofdiscrete pores having a size-selectivity based on a diameter of each ofthe plurality of discrete pores for passage of hydrogen across thegraphene membrane for detection by a sensor device, and having thesize-selectivity for inhibition of passage of methane across thegraphene membrane so as to restrict the methane from contact with thesensor device and thus to protect the sensor device from contaminationthat reduces a sensitivity of the sensor device to detect a presence ofthe hydrogen, the diameter of each of the plurality of discrete pores ofthe graphene membrane is 2.5 Angstroms, and a hydrogen and methaneseparation selectivity of the graphene membrane is 10^23:1 based on thediameter of each of the plurality of discrete pores, the hydrogen isselectively permeated through the discrete pores of the graphenemonolayer by employment of a gradient across the graphene monolayer, andthe gradient includes one or more of a temperature gradient, a pressuregradient, a concentration gradient, a polarity gradient, and anelectrochemical potential gradient; instruct the substrate source toprovide the substrate to support the graphene membrane, wherein aportion of a surface of the substrate is depressed to form a cavity inthe surface of the substrate; and instruct the sensor device applicatorto position the sensor device within the cavity of the surface of thesubstrate, wherein the sensor device is confined below the surface ofthe substrate by being positioned within the cavity, wherein the sensordevice is configured to detect the presence of the hydrogen that crossesthe graphene membrane, and wherein the sensor device comprises a rigidgraphene sensor deposited with palladium nanoparticles to detect thepresence of the hydrogen.
 9. The system of claim 8, wherein thecontroller is further configured to: instruct a sample manipulator tosupport formation of the graphene membrane from the graphene monolayerwith the plurality of discrete pores, which have a uniform pore size.10. The system of claim 9, wherein the controller is further configuredto: instruct a graphene perforation apparatus to form the plurality ofdiscrete pores in the graphene monolayer by removal of graphene carbonatoms from a plurality of locations within the graphene monolayer,wherein the plurality of discrete pores include a plurality of carbonvacancy defects in the graphene monolayer such that the graphenemonolayer has uniform pore sizes throughout.
 11. The system of claim 10,wherein the graphene perforation apparatus is further configured to:form the plurality of discrete pores in the graphene monolayer bycausing one or more of the plurality of carbon vacancy defects in thegraphene monolayer by employment of one or more of: UV-induced oxidativeetching, ion beam etching, and/or lithographic masking coupled withoxygen plasma etching such that the plurality of discrete pores have thediameter that is selective for the passage of the hydrogen.
 12. Thesystem of claim 11, wherein the controller is further configured to:instruct a hydrogen passivation source to passivate the one or more ofthe plurality of carbon vacancy defects in the graphene monolayer withhydrogen.
 13. The system of claim 11, wherein the controller is furtherconfigured to: instruct an apparatus to form the cavity in the surfaceof the substrate.
 14. The system of claim 8, wherein the controller isfurther configured to: instruct an electrode applicator to couple thesensor device with the substrate by an insulation frame and electrodecontacts.